NINDS Rasmussen's Encephalitis Information Page

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What is Rasmussen's Encephalitis?

Rasmussen’s encephalitis is a rare, chronic inflammatory neurological disease that usually affects only one hemisphere of
the brain. It usually occurs in children under the age of 10 (more rarely in adolescents and adults), and is characterized
by frequent and severe seizures, loss of motor skills and speech, paralysis on one side of the body (hemiparesis), inflammation
of the brain (encephalitis), and mental deterioration. Most individuals with Rasmussen’s encephalitis will experience frequent
seizures and progressive brain damage in the affected hemisphere of the brain over the course of the first 8 to 12 months,
and then enter a phase of permanent, but stable, neurological deficits. Rasmussen’s encephalitis has features of an autoimmune
disease in which immune system cells enter the brain and cause inflammation and damage. Research is ongoing into the causes
of this rare disease.

Is there any treatment?

Anti-epileptic drugs are usually not effective in controlling seizures. Recent studies have shown some success with treatments
that suppress or modulate the immune system, in particular those that use corticosteroids, intravenous immunoglobulin, or
tacrolimus. Surgery to control seizures may be performed in later stages of the disease when neurological deficits stabilize.
Surgical procedures, such as functional hemispherectomy and hemispherotomy, may reduce the frequency of seizures and also
improve behavior and cognitive abilities.

What is the prognosis?

The prognosis for individuals with Rasmussen’s encephalitis varies. Despite the advances in medical treatment, none has yet
been shown to halt the progress of the disease in the long term. The disorder may lead to severe neurological deficits or
it may cause only milder impairments. For some children, surgery decreases seizures. However, most individuals with Rasmussen’s
encephalitis are left with some paralysis, cognitive deficits, and problems with speech. In some cases, the disease can progress
to involve the opposite brain hemisphere.

What research is being done?

The National Institute of Neurological Disorders and Stroke (NINDS) conducts research related to Rasmussen’s encephalitis
in its laboratories at the National Institutes of Health (NIH), and also supports additional research through grants to major
research institutions across the country. Much of this research focuses on finding better ways to prevent, treat, and ultimately
cure progressive neurological disorders, such as Rasmussen’s encephalitis.

Prepared by:
Office of Communications and Public Liaison
National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892

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on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined
that patient or is familiar with that patient's medical history.

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